Many internal combustion engines utilize Gasoline Direct Injection (GDI) to increase the power efficiency and range over which the fuel can be delivered to the cylinder. One potential issue with GDI is that under lower fuel pressures the fuel may not sufficiently mix with the air in the cylinder. Insufficient mixing may decrease engine power and efficiency, and increase emissions, at least under some conditions. For example, during cold engine starts, and before the catalytic converter is activated, insufficient mixing as a result of lower fuel pressure may exacerbate cold start emissions.
In one example, a fuel delivery system includes a lower pressure fuel pump and a high pressure fuel pump in combination to achieve a higher fuel pressure. However, at startup the two-pump system may require a longer duration to pump fuel at the higher fuel pressure, which may result in engine miss-starts. Moreover, the consistently higher fuel pressure may cause increased wear on components of the fuel delivery system.
One approach to provide temporarily increased fuel pressure during startup may include utilizing a fuel pressure regulator comprising: a body forming an inlet and an outlet; a seal element positioned intermediate the inlet and the outlet; an armature positioned to apply force to the seal element; and a solenoid coiled around the armature, with excitation of the solenoid causing a change in at least one of a position of the armature relative to the seal element and a force applied by the armature to the seal element to vary a regulated fuel pressure set-point at which fuel flows through the outlet.
By integrating a solenoid into the design of the regulator, the force applied to the seal element of the fuel pressure regulator may be adjusted on demand as operating conditions vary to adjust a fuel pressure set-point. In this way, fuel pressure may be temporarily increased at startup for improved combustion. Moreover, by utilizing the fuel pressure regulator, the fuel pressure set-point may be decreased after startup to reduce wear on fuel delivery system components. In this way, the operational lifetime of the fuel delivery system may be increased.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.